Clamping Assembly and Process Valve

This disclosure relates generally to valve assemblies, and more particularly to clamping assemblies for process valves, such as diaphragm valves, that secure a valve diaphragm and a valve drive to a valve body.

Process valves, including diaphragm valves, are widely used in fluid handling systems for controlling flow and isolating process media. These valves require reliable sealing between the valve diaphragm and the valve body to ensure leak-proof operation, particularly in applications involving corrosive, hazardous, or high-purity fluids.

Conventional clamping mechanisms for securing diaphragms in such valves often involve multi-part assemblies or require high actuation forces, which can complicate installation and maintenance. Furthermore, inadequate clamping or over-tightening can lead to diaphragm damage, sealing failure, or reduced component longevity.

The present disclosure provides a clamping assembly that addresses these issues through a gear-driven mechanism incorporating a worm shaft and a rotatable clamping insert. The insert translates rotational input into precise axial motion to securely clamp the outer collar of the valve diaphragm between a clamping element and the valve body. The assembly integrates self-locking thread geometries to maintain clamping force without back-driving, and may include safety features such as a torque-limiting clutch or predetermined breaking point to prevent damage from excessive torque. Additionally, a cylindrical drive mounting sleeve allows rigid, coaxial integration of the valve drive, further enhancing mechanical stability and reducing stress concentrations. This design improves serviceability, reduces required assembly force, and enhances the operational durability and safety of the process valve.

A first aspect of the description relates to a clamping assembly for a process valve, in particular a diaphragm valve, wherein the clamping assembly comprises: a housing with an interface for connection to a valve body; a gear mechanism supported on the housing, wherein the gear mechanism comprises a worm shaft mounted rotatably in the housing, wherein the gear mechanism comprises a clamping insert mounted in the housing so as to rotate about an adjustment axis, the worm gear teeth of said clamping insert being in engagement with the worm shaft, and wherein an external thread of the rotatable clamping insert is in engagement with an internal thread of the housing in order to move the clamping insert axially along the adjustment axis and relative to the housing by the rotation of said clamping insert; and a clamping element arranged on the output of the gear mechanism, wherein the clamping element comprises a pressing surface, which is designed to clamp a lateral outer collar of a valve diaphragm of the process valve between the clamping element and the valve body.

Advantageously, the valve diaphragm can be easily clamped using the proposed worm drive and the clamping insert that is axially movable in the housing. Advantageously, only a small actuating force is required for this purpose.

In one example, a cylindrical drive mounting sleeve for rigidly fixing a valve drive to the valve body extends from a side of the clamping assembly that faces the valve drive into the clamping assembly, wherein the cylindrical drive mounting sleeve comprises a through-opening running along the adjustment axis, for receiving the drive rod of the valve drive.

Advantageously, the drive rod is arranged at least in portions within the drive mounting sleeve. In addition, the drive rod can be guided axially through the drive mounting sleeve.

In one example, the clamping insert entrains an outer collar of the drive mounting sleeve during a movement along the adjustment axis in the direction of the valve body.

This ensures that the valve drive is rigidly fixed by means of the clamping insert.

In one example, an outer collar of the drive mounting sleeve is arranged at least in portions between the clamping insert and the clamping element.

This shifts the location of the connection between the valve body and the valve drive in the direction of the valve body. This is advantageous since the force path between the tensile stress on the housing of the clamping assembly and the compressive stress on the drive mounting sleeve and on the clamping element is shortened, which improves the fatigue strength of the connection during operation of the process valve.

In one example, a torque transmission portion of the worm shaft is accessible from outside the clamping assembly.

A technician can thus use a powered or non-powered hand tool to assemble and disassemble the process valve for diaphragm replacement. Disassembly and assembly are simplified by the accessible single torque transmission portion.

In one example, a predetermined breaking point is arranged between the torque transmission portion of the worm shaft and a worm flank portion of the worm shaft that is in engagement with the worm gear teeth of the clamping insert.

If the torque is excessive, the predetermined breaking point breaks and prevents destruction of the gear mechanism, the valve diaphragm, or other components of the process valve.

In one example, a safety clutch is arranged between the torque transmission portion of the worm shaft and the worm flank portion of the worm shaft that is in engagement with the worm gear teeth of the clamping insert.

The safety clutch effectively prevents the introduction of excessive torque since it opens and interrupts the torque transmission when a torque threshold value is exceeded. This effectively prevents damage to the clamping assembly.

In one example, the worm shaft is made of a metal alloy at least in the engagement region with the clamping insert and the clamping insert is made of a plastic at least in the engagement region with the worm shaft, or the clamping insert is made of a metal alloy at least in the engagement region with the worm shaft and the worm shaft is made of a plastic at least in the engagement region with the clamping insert.

This advantageously reduces the torque that is to be introduced into the worm shaft and is necessary for an axial movement of the clamping insert or for introducing the clamping force.

In one example, the worm gear teeth of the clamping insert are made of the plastic, wherein the external thread of the clamping insert is made of the metal alloy or another metal alloy.

This hybrid clamping insert makes it possible to reduce the torque that is to be introduced into the worm shaft and is necessary for clamping the valve diaphragm.

In one example, a worm drive comprising the clamping insert and the worm shaft is designed to be self-locking.

This advantageously prevents unintentional relaxation of the outer collar of the valve diaphragm.

In one example, the external thread of the clamping insert and the engaging internal thread of the housing are designed to be self-locking.

Advantageously, this not only effectively prevents unintentional relaxation of the outer collar of the valve diaphragm. Rather, the trapezoidal thread also rigidly fixes the valve drive to the valve body.

In one example, the clamping insert and the worm shaft are configured to perform a rotational movement of the clamping insert due to the engagement with the rotating worm shaft, wherein the clamping insert and the housing are configured to perform an axial movement relative to the housing along the adjustment axis through the rotational movement of the clamping insert and the engagement of the external thread of the clamping insert in the internal thread of the housing.

A further aspect of the description relates to a process valve comprising the valve drive; a valve body; and the clamping assembly according to the first aspect, wherein the clamping assembly is arranged between the valve drive and the valve body.

In one example, an axial movement of the clamping insert in the direction of the valve body rigidly connects the housing of the clamping assembly and the valve drive to the valve body in that the clamping insert exerts a tensile force on the valve body via the housing and the clamping insert causes a compressive force on the drive mounting sleeve and the valve body via the clamping element. Further details and embodiments of the disclosure can be found in the following description, by which embodiments of the disclosure are further described and explained.

Aspects of the present disclosure relate to a clamping assembly for a process valve, such as a diaphragm valve, that provides precise, tool-assisted clamping of a valve diaphragm and rigid coupling of a valve drive to a valve body. The assembly includes a worm-driven clamping insert that translates rotational input into axial clamping force, enabling reliable sealing and mechanical retention. Design features such as self-locking threads, accessible torque input, and optional overload protection enhance safety, serviceability, and operational reliability.

As used herein, “adjustment axis” refers to the longitudinal axis along which the clamping insert moves relative to the housing to apply or release a clamping force. This axis typically aligns with the central axis of the process valve assembly.

As used herein, “clamping insert” refers to a rotatable component supported within the housing and operatively engaged with both a worm shaft and a threaded interface.

Rotation of the clamping insert causes axial movement along the adjustment axis to generate clamping force.

As used herein, “worm shaft” refers to a helically threaded shaft mounted for rotation about an axis transverse to the adjustment axis, and configured to engage worm gear teeth on the clamping insert to impart rotational motion.

As used herein, “self-locking” refers to a mechanical condition in which applied torque results in axial displacement that is maintained without continued torque input, and which resists reverse motion due to friction or geometric design.

As used herein, “valve drive” refers to an actuator assembly configured to move a drive rod axially to actuate a valve diaphragm, thereby controlling the open or closed state of the valve.

As used herein, “drive mounting sleeve” refers to a cylindrical coupling structure that rigidly connects the valve drive to the clamping assembly. It surrounds the drive rod and may include an outer collar that is mechanically engaged by the clamping insert.

As used herein, “clamping element” refers to a component positioned between the clamping insert and the valve body, including a pressing surface configured to compress an outer collar of the valve diaphragm against the valve body to provide a seal.

As used herein, “predetermined breaking point” refers to a structurally weakened region of the worm shaft configured to fail under excess torque, thereby protecting surrounding components from damage.

As used herein, “safety clutch” refers to a torque-limiting mechanism that interrupts torque transmission when a predefined threshold is exceeded, preventing mechanical overload.

As used herein, “valve diaphragm” refers to a flexible membrane configured to open or close fluid flow in response to axial actuation, typically positioned between a valve body and valve drive in a process valve.

show a process valve, in particular a diaphragm valve, in a respective schematic section, in which an adjustment axis S of the process valvelies. The process valvecomprises a valve drive, a valve body, and a clamping assemblyarranged between the valve driveand the valve body.

The clamping assemblycomprises a housingwith an interface-for connection to the valve body.

A gear mechanismof the clamping assemblyis supported on the housing. The gear mechanismcomprises a worm shaftmounted rotatably in the housing. The gear mechanismcomprises a clamping insertmounted in the housingso as to rotate about the adjustment axis S, the worm gear teethof said clamping insert being in engagement with the worm shaft. An external threadof the rotatable clamping insertis in engagement with an internal threadof the housingin order to move the clamping insertaxially along the adjustment axis S and relative to the housingby the rotation of the clamping insert.

A clamping elementarranged at the output of the gear mechanismcomprises a pressing surfacedesigned to clamp a lateral outer collarof a valve diaphragmof the process valvebetween the clamping elementand the valve body.

It is provided in the example that the clamping insertand the worm shaftare configured to perform a rotational movement of the clamping insertdue to the engagement with the rotating worm shaft, and wherein the clamping insertand the housingare configured to perform an axial movement relative to the housingalong the adjustment axis S through the rotational movement of the clamping insertand the engagement of the external threadof the clamping insertin the internal threadof the housing.

A rotation axis N of the worm shaftruns in a perpendicular plane of the adjustment axis.

The worm drive, which is provided by the connection of the worm shaftand the clamping insert, the thread pair, which is provided by the threadof the housingand the threadof the clamping insert, the bracing of the housingon the valve body, and the clamping elementare configured such that an axial movement of the clamping insertgenerates a clamping force between the outer collarof the valve diaphragmand the valve body, whereby the process valveis sealed to the outside.

The worm drive, which is provided by the connection of the worm shaftand the clamping insert, the thread pair, which is provided by the threadof the housingand the threadof the clamping insert, the bracing of the housingon the valve body, and the clamping elementare configured such that an axial movement of the clamping insertgenerates a clamping force between a clamping surfaceand a counter clamping surfaceof the valve body, whereby the housingof the clamping assemblyand the valve bodyare rigidly fixed to each other.

The clamping elementis arranged between the outer collarof the drive mounting sleeveand the valve body.